Fertilization and embryo development in vivo occurs in appropriate conditions in the mammalian reproductive tract. However in assisted reproductive technology (ART) embryos and oocytes are exposed to certain factors such as temperature, O2 pressure and pH fluctuations that may affect embryo development and viability in vitro. In Preimplantation Genetic Screening program (PGS) the investigators need to culture the embryos until day 5 so the requirement of culture techniques must be optimal to produce acceptable blastocyst rates. As it has been shown before, embryo culture conditions have the potential to impact biopsied embryos and hence PGS success rates.